Four-axis four-subdividing interferometer thermal drift reduction
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Solution Overview
Problem
Current multi-axis interferometers face challenges in achieving high measurement accuracy due to inconsistent temperature drift and nonlinear errors in light splitting systems, which are difficult to adjust and process, especially with block optical components that require precise coatings and fixed geometrical positions.
Innovation Solution
A four-axis four-subdividing interferometer design featuring a light splitting module with three 50% plane beam splitters and 45-degree full-reflecting mirrors, allowing for easy adjustment and consistent temperature drift, combined with an interference module using polarizing beam splitters and adjustable 45-degree mirrors, ensuring equal energy distribution and independent beam adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If block optical light splitting component with multiple coatings is used, then light splitting function is achieved, but manufacturing precision and coating difficulty increase significantly
Solution Approach 1:
The patent divides the light splitting function into multiple independent plane beam splitters (first, second, and third 50% beam splitters) rather than using a single block optical component with multiple coatings. Each beam splitter is a separate, simpler component that can be manufactured and coated more easily, reducing the overall manufacturing precision requirements while maintaining the light splitting functionality.
2Reliability
If block optical light splitting component is used, then light splitting is achieved, but temperature drift consistency deteriorates
Solution Approach 1:
The patent uses multiple separate plane beam splitters instead of a single block optical component. This segmentation allows each component to have its own thermal characteristics and path lengths, enabling better control and consistency of temperature drift across different light paths. The independent components can be positioned and adjusted to compensate for thermal effects.
Solution Approach 2:
The patent arranges the beam splitters and light paths in a three-dimensional configuration with specific spatial relationships (vertical and horizontal arrangements). This dimensional arrangement allows for equalizing the optical path lengths through the quartz glass medium by adjusting the vertical distances between components, thereby achieving consistent temperature drift compensation across multiple light paths.
3Ease of operation
If block optical light splitting component with fixed geometry is used, then structural stability is achieved, but light path adjustability deteriorates
Solution Approach 1:
The patent introduces adjustable elements into the previously fixed geometric structure. Specifically, the vertical distances between the first beam splitter and second beam splitter, and between the second beam splitter and third beam splitter, can be adjusted independently. This dynamic adjustability allows for optimization of light path lengths and alignment without requiring a completely reconfigurable system, balancing ease of operation with controlled device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly reduces measurement errors from thermal drift and nonlinear errors, enhances optical efficiency, and simplifies component processing and light path adjustments, achieving high precision and stability with minimal temperature drift and low nonlinear errors.
Implementation Method 1
the first 45-degree plane beam splitter dividing the incident polarization laser into a transmission beam and a reflection beam with equal energy
Implementation Method 2
a beam of double-frequency laser output from the laser being divided into four beams which have equal energy and are parallel to each other after passing through the four-axis light splitting module
Implementation Method 3
The four parallel beams are used as the precision measurement of four degrees of freedom
Implementation Method 4
the interferometer has the advantages that the components are easy to process, the light path adjustment is easy, nonlinear errors are fewer, the temperature drift of the light beams of the light paths is consistent
Data Source
AI summary
Four-axis four-subdividing interferometer comprising a four-axis light splitting module and an interference module which are sequentially arranged along the incident direction of polarization orthogonal double-frequency laser. The four-axis light splitting system comprises three 50% plane beam splitters and three 45-degree plane reflecting mirrors. The invention comprises a four-axis four-subdividing plane mirror interferometer and a four-axis four-subdividing differential interferometer. In the differential interferometer, an adjustable 45-degree reflecting mirror is used to guide the reference light to a reference reflecting mirror which is arranged in the same direction as a measurement mirror and fixed on the moving object.